1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * ACPI helpers for the MDIO (Ethernet PHY) API
4 *
5 * This file provides helper functions for extracting PHY device information
6 * out of the ACPI ASL and using it to populate an mii_bus.
7 */
8
9#include <linux/acpi.h>
10#include <linux/acpi_mdio.h>
11#include <linux/bits.h>
12#include <linux/dev_printk.h>
13#include <linux/fwnode_mdio.h>
14#include <linux/module.h>
15#include <linux/types.h>
16
17MODULE_AUTHOR("Calvin Johnson <calvin.johnson@oss.nxp.com>");
18MODULE_LICENSE("GPL");
19MODULE_DESCRIPTION("ACPI MDIO bus (Ethernet PHY) accessors");
20
21/**
22 * __acpi_mdiobus_register - Register mii_bus and create PHYs from the ACPI ASL.
23 * @mdio: pointer to mii_bus structure
24 * @fwnode: pointer to fwnode of MDIO bus. This fwnode is expected to represent
25 * @owner: module owning this @mdio object.
26 * an ACPI device object corresponding to the MDIO bus and its children are
27 * expected to correspond to the PHY devices on that bus.
28 *
29 * This function registers the mii_bus structure and registers a phy_device
30 * for each child node of @fwnode.
31 */
32int __acpi_mdiobus_register(struct mii_bus *mdio, struct fwnode_handle *fwnode,
33 struct module *owner)
34{
35 struct fwnode_handle *child;
36 u32 addr;
37 int ret;
38
39 /* Mask out all PHYs from auto probing. */
40 mdio->phy_mask = GENMASK(31, 0);
41 ret = __mdiobus_register(bus: mdio, owner);
42 if (ret)
43 return ret;
44
45 ACPI_COMPANION_SET(&mdio->dev, to_acpi_device_node(fwnode));
46
47 /* Loop over the child nodes and register a phy_device for each PHY */
48 fwnode_for_each_child_node(fwnode, child) {
49 ret = acpi_get_local_address(ACPI_HANDLE_FWNODE(child), addr: &addr);
50 if (ret || addr >= PHY_MAX_ADDR)
51 continue;
52
53 ret = fwnode_mdiobus_register_phy(bus: mdio, child, addr);
54 if (ret == -ENODEV)
55 dev_err(&mdio->dev,
56 "MDIO device at address %d is missing.\n",
57 addr);
58 }
59 return 0;
60}
61EXPORT_SYMBOL(__acpi_mdiobus_register);
62